Can't Find any of the add-ons on "Testing" for 2.8
The Testing Add-ons are only shipped with the experimental buildbot releases, see DevTalk. This is even true if you would compile Blender yourself. Go to the Download section at blender.org and scroll down to the area where the experimental versions can be downloaded:



Those builds should contain the Testing Add-ons you are looking for. If you want to use it in your 2.80 stable release too, you can simply extract it from the zip archive, and put it into the scripts/addons_contrib folder of your 2.80 installation, or your Blender user scripts directory: